How To Accept a File POST

Question

I'm using asp.net mvc 4 webapi beta to build a rest service. I need to be able to accept POSTed images/files from client applications. Is this possible using the webapi? Below is how action I am currently using. Does anyone know of an example how this should work?

[HttpPost]
public string ProfileImagePost(HttpPostedFile profileImage)
{
    string[] extensions = { ".jpg", ".jpeg", ".gif", ".bmp", ".png" };
    if (!extensions.Any(x => x.Equals(Path.GetExtension(profileImage.FileName.ToLower()), StringComparison.OrdinalIgnoreCase)))
    {
        throw new HttpResponseException("Invalid file type.", HttpStatusCode.BadRequest);
    }

    // Other code goes here

    return "/path/to/image.png";
}

Answer 1

Here are two ways to accept a file. One using in memory provider MultipartMemoryStreamProvider and one using MultipartFormDataStreamProvider which saves to a disk. Note, this is only for one file upload at a time. You can certainty extend this to save multiple-files. The second approach can support large files. I've tested files over 200MB and it works fine. Using in memory approach does not require you to save to disk, but will throw out of memory exception if you exceed a certain limit.

        private async Task<Stream> ReadStream()
    {
        Stream stream = null;
        var provider = new MultipartMemoryStreamProvider();
        await Request.Content.ReadAsMultipartAsync(provider);
        foreach (var file in provider.Contents)
        {
            var buffer = await file.ReadAsByteArrayAsync();
            stream = new MemoryStream(buffer);
        }

        return stream;
    }

private async Task<Stream> ReadLargeStream()
    {
        Stream stream = null;
        string root = Path.GetTempPath();
        var provider = new MultipartFormDataStreamProvider(root);
        await Request.Content.ReadAsMultipartAsync(provider);
        foreach (var file in provider.FileData)
        {
            var path = file.LocalFileName;
            byte[] content = File.ReadAllBytes(path);
            File.Delete(path);
            stream = new MemoryStream(content);
        }

        return stream;
    }

Answer 2

I used Mike Wasson's answer before I updated all the NuGets in my webapi mvc4 project. Once I did, I had to re-write the file upload action:

    public Task<HttpResponseMessage> Upload(int id)
    {
        HttpRequestMessage request = this.Request;
        if (!request.Content.IsMimeMultipartContent())
        {
            throw new HttpResponseException(new HttpResponseMessage(HttpStatusCode.UnsupportedMediaType));
        }

        string root = System.Web.HttpContext.Current.Server.MapPath("~/App_Data/uploads");
        var provider = new MultipartFormDataStreamProvider(root);

        var task = request.Content.ReadAsMultipartAsync(provider).
            ContinueWith<HttpResponseMessage>(o =>
            {
                FileInfo finfo = new FileInfo(provider.FileData.First().LocalFileName);

                string guid = Guid.NewGuid().ToString();

                File.Move(finfo.FullName, Path.Combine(root, guid + "_" + provider.FileData.First().Headers.ContentDisposition.FileName.Replace("\"", "")));

                return new HttpResponseMessage()
                {
                    Content = new StringContent("File uploaded.")
                };
            }
        );
        return task;
    }

Apparently BodyPartFileNames is no longer available within the MultipartFormDataStreamProvider.

Answer 3

API Controller :

[HttpPost]
public HttpResponseMessage Post()
{

        HttpRequestMessage request = this.Request;

            if (!request.Content.IsMimeMultipartContent() || System.Web.HttpContext.Current.Request.Files.Count < 1)
            {
               //TODO
            }
            else
            {
                string root = System.Web.HttpContext.Current.Server.MapPath("~/App_Data");
                var provider = new MultipartFormDataStreamProvider(root);

                try
                {
                    Request.Content.ReadAsMultipartAsync(provider);
                    List<String> payload = new List<string>();

                    foreach (var file in provider.FileData)
                    {                       
                        var path = file.LocalFileName;
                        byte[] byteArray = File.ReadAllBytes(path);

                    }

                }
                catch (System.Exception e)
                {
                    //TODO
                }
            }


    return Request.CreateResponse(HttpStatusCode.Created);
}

Answer 4

[HttpPost]
public JsonResult PostImage(HttpPostedFileBase file)
{
    try
    {
        if (file != null && file.ContentLength > 0 && file.ContentLength<=10485760)
        {
            var fileName = Path.GetFileName(file.FileName);                                        

            var path = Path.Combine(Server.MapPath("~/") + "HisloImages" + "\\", fileName);

            file.SaveAs(path);
            #region MyRegion
            ////save imag in Db
            //using (MemoryStream ms = new MemoryStream())
            //{
            //    file.InputStream.CopyTo(ms);
            //    byte[] array = ms.GetBuffer();
            //} 
            #endregion
            return Json(JsonResponseFactory.SuccessResponse("Status:0 ,Message: OK"), JsonRequestBehavior.AllowGet);
        }
        else
        {
            return Json(JsonResponseFactory.ErrorResponse("Status:1 , Message: Upload Again and File Size Should be Less Than 10MB"), JsonRequestBehavior.AllowGet);
        }
    }
    catch (Exception ex)
    {

        return Json(JsonResponseFactory.ErrorResponse(ex.Message), JsonRequestBehavior.AllowGet);

    }
}

Answer 5

I'm surprised that a lot of you seem to want to save files on the server. Solution to keep everything in memory is as follows:

[HttpPost, Route("api/upload")]
public async Task<IHttpActionResult> Upload()
{
    if (!Request.Content.IsMimeMultipartContent())
        throw new HttpResponseException(HttpStatusCode.UnsupportedMediaType); 

    var provider = new MultipartMemoryStreamProvider();
    await Request.Content.ReadAsMultipartAsync(provider);
    foreach (var file in provider.Contents)
    {
        var filename = file.Headers.ContentDisposition.FileName.Trim('\"');
        var buffer = await file.ReadAsByteArrayAsync();
        //Do whatever you want with filename and its binary data.
    }

    return Ok();
}

Answer 6

Here is a quick and dirty solution which takes uploaded file contents from the HTTP body and writes it to a file. I included a "bare bones" HTML/JS snippet for the file upload.

Web API Method:

[Route("api/myfileupload")]        
[HttpPost]
public string MyFileUpload()
{
    var request = HttpContext.Current.Request;
    var filePath = "C:\\temp\\" + request.Headers["filename"];
    using (var fs = new System.IO.FileStream(filePath, System.IO.FileMode.Create))
    {
        request.InputStream.CopyTo(fs);
    }
    return "uploaded";
}

HTML File Upload:

<form>
    <input type="file" id="myfile"/>  
    <input type="button" onclick="uploadFile();" value="Upload" />
</form>
<script type="text/javascript">
    function uploadFile() {        
        var xhr = new XMLHttpRequest();                 
        var file = document.getElementById('myfile').files[0];
        xhr.open("POST", "api/myfileupload");
        xhr.setRequestHeader("filename", file.name);
        xhr.send(file);
    }
</script>